Aboveground Modular, Permeable Reactive Barrier System for Rainfall Runoff Treatment

ABSTRACT

A method for the treatment of liquid runoff, such as rainfall or irrigation runoff, to prevent the transportation of solutes. The method comprises permeable reactive barriers constructed to be permeable to rainfall runoff streams, and to effectively contact the stream with the contained media to facilitate removal of solutes from the runoff stream. Said method of rainfall runoff treatment is easily deployed in a variety of settings and easily maintained over long periods of time.

FIELD OF THE INVENTION

The present invention relates generally to the field of pollutionabatement. More particularly, it concerns a system of treating liquidrunoff, such as rainfall or irrigation runoff, to prevent thetransportation of solutes wherein permeable barrier structures areassembled in the path of runoff streams with single or multiplecontainers of media that remove the solute(s) from the runoff stream asthe stream flows through the structure.

Agricultural, industrial, commercial and public facilities often containsubstances on or near the ground surface that may achieve mobility assolutes in accumulated liquid runoff and leave the premises in a runoffstream. Methods to mitigate the transfer of solutes in runoff streamsinclude the construction of catchment basins wherein the runoff streamaccumulates until it either evaporates or permeates into the ground,grass filter strips wherein runoff stream's velocity is reduced allowinginfiltration, and drainage systems incorporating buried permeablebarriers wherein runoff drainage is directed through a buried barriercomprised of media that immobilizes the solutes as the drainage passesthrough. These present methods are limited in application byinstallation requirements that are not suitable for many settings.Catchment basins require a large space that may not be availableparticularly at established facilities. Grass filter strips may alsorequire a large space and may be less effective on steep slopes. Buriedpermeable barriers may require an additional drainage system to directthe runoff through the barrier.

Performance of grass filtration strips may not be adequate during highrainfall events and the long term performance of buried permeablebarriers may be limited by the effective capacity of the media utilizedto act on the solute(s) and by decreases in permeability requiringdifficult maintenance.

SUMMARY OF THE INVENTION

Accordingly the present invention provides a system for the treatment ofliquid runoff, such as rainfall or irrigation runoff, comprisingpermeable barriers that allow the liquid runoff to effectively contact amedia within the permeable barrier to facilitate removal of thesolute(s) from the runoff stream. One embodiment of this systemcomprises single or multiple containers of media. The containers ofmedia are constructed to be permeable to liquid runoff streams, toeffectively contact the contained media with the liquid runoff stream tofacilitate removal of the solute(s) from the runoff stream, and toeasily attach together to collectively form permeable barriers ofvarious shapes and sizes suitable for many settings and runoff flowrates, placed in the path of runoff streams on the ground surface. Saidsystem for liquid runoff treatment is easily deployed in a variety ofsettings and easily maintained over long periods of time.

Following long-standing patent law convention, the terms “a” and “an”mean “one or more” when used in this application, including the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings form part of the present specification and areincluded to further demonstrate certain aspects of the presentinvention. The invention may be better understood by reference to one ormore of these drawings in combination with the detailed description ofspecific embodiments presented herein.

FIG. 1 depicts a plot of land containing a substance being firstmobilized by liquid (rainfall) runoff and subsequently captured as therunoff stream passes through the permeable barrier.

FIG. 2 depicts an individual media container constructed of pliablenetting with holes on reinforced end strips to facilitate anchorage andattachment to other containers.

FIG. 3 depicts multiple media containers anchored to the ground surfaceand attached to each other forming a permeable barrier structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a system of treating liquid runoff, suchas rainfall or irrigation runoff, to prevent the transportation ofsolutes. The system comprises the assembly of individual containers ofmedia constructed to be permeable to runoff streams, to effectivelycontact the runoff stream with the contained media to facilitate removalof solutes from the runoff stream, and to easily attach together tocollectively form permeable barrier structures of various shapes andsizes in the path of runoff streams. Advantages of the present systeminclude the ease of deployment and maintenance of the permeablebarriers. For example, the individual containers of media can be of asize and weight that can be handled manually for installation andmaintenance and the barriers can be constructed on the surface in thepath of rainfall runoff.

The system of the invention is useful for capture or immobilization of avariety of contained solutes from rainfall runoff using a variety ofsorbent or active media. The media has a surface that takes up and holdssolutes, and includes zeolites, cation exchange media, activated carbon,and reactive media for example. A solute is a dissolved substance. In apreferred embodiment, a substantially solid zeolite sorbent material(zeolite) is the media used for removal of ammonia or ammonium (ammonia)in solution in rainfall runoff from agricultural land as the runoffpasses through a permeable barrier placed in the path of the runoffstream. The permeable barrier is comprised of individual containers thatare constructed to contain the zeolite pieces, allow fluid flow throughthe containers and across the zeolite pieces, conform in shape to theground surface, provide means to anchor to the ground, provide means toattach to other similar containers, and resist degradation over longperiods of time ranging from months to years.

Ammonia is present on many agricultural lands as a result of commercialfertilizer application to crops, poultry litter and dairy cattle manureapplication to pastures, and other activities. Ammonia is a beneficialsubstance on the agricultural land but when mobilized by rainfall runoffand taken off premises into streams and other bodies of water it can bea harmful pollutant. In many settings it is not practical to impound therainfall runoff or to utilize grass filter strips to mitigate ammoniatransport from the premises. In many of these cases the preferredembodiment allows for a barrier to ammonia transport to be placed on theground surface in the path of the runoff stream that permits drainageand is easy for agricultural landowner/operators to install andmaintain. It is the aim of the present invention to inhibit thetransportation of solutes in rain water drainage using a barrier withoutinhibiting the transportation of the rain water along the drainagepathway. It is recognized that other barriers can be constructed withmultiple containers for drainage control, for example sand bag barriersthat are constructed to inhibit the flow of drainage. One embodiment ofthe present invention may utilize the characteristic of sand bags inthat the shape of the bags or containers conform to the ground surfaceand other adjacent bags forming a structure that does not requireanchorage or attachment of the individual containers.

As used herein, the term “zeolite” means a three dimensional,microporous, crystalline solid that includes aluminum, silicon andoxygen in a regular framework. Natural zeolite material exist that maybe mined and crushed into various size pieces. In the preferredembodiment the natural zeolite species utilized is clinoptilolitebecause of a high affinity for ammonia. The preferred size of thezeolite pieces is greater than three-eighths of an inch and less thantwo inches in diameter. After prolonged use the clinoptilolite media canbe maintained within the individual containers, for example, by washingout accumulated silt, eluting accumulated ammonia by washing withammonia free water, or desorbing accumulated ammonia by rotating thecontainers to expose to sunlight.

Referring to FIG. 1 a plot of agricultural land 1 is depicted containingammonia 2 on the surface and a permeable barrier structure 6 comprisedof multiple containers of clinoptilolite pieces 8. The individualcontainers of clinoptilolite media 8 are fastened together to form thepermeable barrier structure 6, the bottom most layer of containers 8 isanchored with stakes to the ground surface 1. Accumulated rainfallmobilizes some of the ammonia 2 in rainfall runoff 4. The rainfallrunoff 4 flows along the existing drainage paths to the permeablebarrier structure 6. The ammonia containing rainfall runoff 4 flowsthrough the permeable barrier structure 6 wherein the clinoptilolitemedia takes up the ammonia. Rainfall runoff 10 exits the permeablebarrier structure containing little or no ammonia.

Referring to FIG. 2, a preferred embodiment of an individual container16 of clinoptilolite media 12 is comprised of netting 18 forming a bagwith two reinforced ends 14. The netting 18 is formed with material thatresists photodegradation, has apertures small enough to contain theclinoptilolite media, sufficient mechanical strength to resist ruptureduring transportation, installation, and maintenance, and issufficiently pliable to conform to the shape of the ground surface.Reinforced ends 14 are comprised of a material with suitable strength tosecurely close netting 18 and to accommodate optional anchorage holes 21and optional attachment holes 20 and is either sewn or welded onto thenetting. If added anchoring is desired, anchorage holes 21 andattachment holes 20 may be punched through reinforced end material 14and may include reinforcing grommets (not shown). In the preferredembodiment containers 16 are sized to hold approximately 50 pounds ofclinoptilolite media sized between three-eighths and two inches indiameter.

Referring to FIG. 3, permeable barrier structure 22 is comprised ofindividual containers 16 attached together with attachment cords 24through attachment holes 20 and anchored to the ground surface withanchorage stakes 28 inserted through anchorage holes 21 and driven intothe ground surface. Permeable barrier structures 22 can be assembledwith various widths, lengths, and heights using combinations of multiplecontainers in order to accommodate site requirements based on the groundsurface geometry of the rainfall runoff flow path, the rates of rainfallrunoff flow, the concentration of ammonia in the rainfall runoff, or thedesired time between required maintenance.

Even though the invention has been described with a certain degree ofparticularity, it is evident that many alternatives, modifications, andvariations will be apparent to those skilled in the art in light of theforegoing disclosure. Accordingly, it is intended that all suchalternatives, modifications, and variations which fall within the spiritand the scope of the invention be embraced by the defined claims.

1. (canceled)
 2. A system of treating liquid runoff to preventtransportation of solutes dissolved in a liquid runoff stream,comprising: multiple modular containers of media placed in the flow pathof a liquid runoff stream to form a permeable barrier that removessolutes from the liquid runoff stream while allowing relativelyunimpeded flow of the liquid stream through said permeable barrier, saidcontainers constructed to permit intra-container fluid flow andintra-container contact between the liquid runoff stream and said media.3. The system of claim 2 wherein said containers are comprised of anouter netting material, said netting material having apertures smallenough to contain said media; and said media contained in said nettingin such a way that said containers are sufficiently pliable to conformto irregular surfaces, such as a ground surface.
 4. The system of claim2 wherein said containers are comprised of means for securing saidcontainers to other containers or to a fixed surface such as the ground.5. The system of claim 4 wherein said means for securing said containerscomprises holes of sufficient strength to facilitate securing of saidcontainers with devices such as ropes, straps, hooks, or stakes.
 6. Thesystem of claim 4 wherein said means for securing said containerscomprises straps fixed to the containers.
 7. A system according to oneof claims 2-6 or 8-10 wherein the media comprises clinoptilolite.
 8. Asystem according to claim 7 wherein the solute comprises ammonia orammomum.
 9. A system according to claim 2 wherein the modular containersare shaped so as to substantially eliminate any gaps, holes or voidsbetween them.
 10. A system according to claim 2 wherein the permeablebarrier is substantially planar relative to the direction of the flowpath of the liquid runoff stream.
 11. A system according to claim 2wherein each of the modular containers forming the permeable barrier hasa substantially planar face relative to the direction of the flow pathof the liquid runoff stream.